This invention relates to the preparation of carbonaceous products from coal. More particularly, it relates to a process for the preparation of green coke products, such as needle-like carbon, coarse mosaic carbon, mosaic carbon, fine mosaic carbon, and glassy carbon, from various types of solvent purified coal formed by dissolving coal in a hydrocarbon solvent, separating insoluble components from the resulting solution, and then removing the solvent therefrom, each type of solvent purified coal being characterized by the (N+O+S)/C atomic ratio thereof having a value in the range specified for one of the foregoing carbonaceous products.
The term "coal" as used herein is intended to comprehend all kinds of coal including bituminous coal, sub-bituminous coal, brown coal, lignite, and grass peat.
The properties of carbonaceous products prepared according to conventional methods are determined solely by the type of raw material used. In industrial applications, petroleum derived heavy oil has been exclusively used as a raw material for needle-like carbon, coarse mosaic carbon, mosaic carbon, and fine mosaic carbon. However, petroleum derived heavy oil is steeply rising in price and, moreover, remarkably lowering in quality. Meanwhile, thermosetting resins such as furfuryl alcohol and furan resin have been used for the preparation of glassy carbon which is an impermeable carbonaceous product useful for the lining of reactors and the like. However, these resins are expensive. Under these circumstances, the supply-demand relations of such carboneous products are becoming more and more strained. Accordingly, there is urgent need of a process for the preparation of such carbonaceous products from a raw material which will be stably and inexpensively available over a long period of time.
Coal, which has a considerable ash content, cannot be used directly as a raw material for such carbonaceous products. It is possible, however, to make coal useful as a raw material for such carbonaceous products by depolymerizing it in a hydrocarbon solvent and separating insoluble components therefrom. When a variety of carbonaceous products as described above are to be prepared from coal, the problem to be solved is how far the depolymerization of coal in a hydrocarbon solvent should be allowed to proceed for the purpose of obtaining a raw material suitable for the preparation of a desired carbonaceous product.